Musculoskeletal Injury Risk Stratification: A Traffic Light System for Military Service Members.

Risk factor identification is a critical first step in informing musculoskeletal injury (MSKI) risk mitigation strategies. This investigation aimed to determine if a self-reported MSKI risk assessment can accurately identify military service members at greater MSKI risk and determine whether a traffic light model can differentiate service members' MSKI risks. A retrospective cohort study was conducted using existing self-reported MSKI risk assessment data and MSKI data from the Military Health System. A total of 2520 military service members (2219 males: age 23.49 ± 5.17 y, BMI 25.11 ± 2.94 kg/m2; and 301 females: age 24.23 ± 5.85 y, BMI 25.59 ± 3.20 kg/m2, respectively) completed the MSKI risk assessment during in-processing. The risk assessment consisted of 16 self-report items regarding demographics, general health, physical fitness, and pain experienced during movement screens. These 16 data points were converted to 11 variables of interest. For each variable, service members were dichotomized as at risk or not at risk. Nine of the 11 variables were associated with a greater MSKI risk and were thus considered as risk factors for the traffic light model. Each traffic light model included three color codes (i.e., green, amber, and red) to designate risk (i.e., low, moderate, and high). Four traffic light models were generated to examine the risk and overall precision of different cut-off values for the amber and red categories. In all four models, service members categorized as amber [hazard ratio (HR) = 1.38-1.70] or red (HR = 2.67-5.82) were at a greater MSKI risk. The traffic light model may help prioritize service members who require individualized orthopedic care and MSKI risk mitigation plans.

The association between kinesiophobia and functional limitations in service members with knee pain.

BACKGROUND: Knee diagnoses account for more than 50% of lower extremity musculoskeletal conditions in non-deployed US Service members. However, there is limited information regarding kinesiophobia in Service members with non-operative knee diagnoses. HYPOTHESES: The objectives of this study were to determine the prevalence of high levels of kinesiophobia in US military Service members with knee pain across different knee diagnoses, and to determine the relationships between kinesiophobia and lower extremity function and/or specific functional limitations in Service members with knee pain. It was hypothesized Service members with knee pain would exhibit high levels of kinesiophobia across all knee diagnoses examined, and higher levels of both kinesiophobia and pain would be associated with worse self-reported function in this population. It was also hypothesized higher levels of kinesiophobia would be associated with functional activities with high knee loading. DESIGN: Retrospective cohort study. LEVEL OF EVIDENCE: IV. METHODS: Sixty-five US Service members presenting to an outpatient physical therapy clinic were included in this study (20 females; age = 30.8 ± 7.7 years; height = 1.74 ± 0.9 m; mass = 80.7 ± 16.2 kg). Inclusion criterion was the presence of knee pain (duration = 50 ± 59 months); exclusion criterion was knee pain as a sequela of knee surgery. Data regarding demographic, pain chronicity, pain by Numeric Rating Scale (NRS), Tampa Scale of Kinesiophobia (TSK), and Lower Extremity Functional Scale (LEFS) were retrospectively obtained from patients' medical records. A high level of kinesiophobia was defined as a TSK score of greater than 37 points. Patient diagnoses included: osteoarthritis (n = 16); patellofemoral pain syndrome (n = 23); and other non-operative knee diagnoses (n = 26). Commonality analysis was utilized to determine the effects of age, height, mass, NRS, and TSK on LEFS score. Predictor values were interpreted as <1% = negligible, >1% = small; >9% = moderate, >25% = large. Additionally, exploratory item-specific analyses examined the strength of the relationships between kinesiophobia and LEFS item responses. Binary logistic regression determined if difficulty with an individual LEFS item could be predicted from either NRS or TSK score. Statistical significance was set at P < 0.05. RESULTS: High levels of kinesiophobia were identified in 43 individuals (66%). NRS and TSK explained 19.4% and 8.6% of the unique variance in LEFS, and 38.5% and 20.5% of total variance, respectively. Age, height, and mass explained negligible to small proportions of the unique variance in LEFS. TSK and NRS were independent predictors for 13/20 individual LEFS items, with odds ratios ranging from 1.12 to 3.05 (P < 0.05). CONCLUSION: The majority of US Service members in this study exhibited high levels of kinesiophobia. Kinesiophobia was significantly related to self-reported functional scores and performance on individual functional tasks in Service members with knee pain. CLINICAL RELEVANCE: Treatment strategies addressing both fear of movement and pain reduction in patients with knee pain may help optimize functional outcomes.

Investigating post-mild traumatic brain injury neuromuscular function and musculoskeletal injury risk: A protocol for a prospective, observational, case-controlled study in service members and active individuals.

INTRODUCTION: Musculoskeletal injury (MSKI) risk is increased following mild traumatic brain injury (mTBI). Increased MSKI risk is present up to 2 years following post-mTBI return-to-duty/activity relative to both non-mTBI peers and to their pre-mTBI selves across a range of populations, including military service members, and professional, college and high school athletes. Despite the well documented increased post-mTBI MSKI risk, the underlying neuromuscular mechanisms contributing to this increased risk have yet to be definitively determined. A number of potential mechanisms have been suggested (eg, aberrant kinematics, dynamic balance impairments, lower voluntary muscle activation), but none have been confirmed with a comprehensive, prospective study. This study aims to: (1) elucidate the neuromuscular control mechanisms following mTBI that contribute to increased MSKI risk, and (2) prospectively track patient outcomes (up to 12 months; MSKI occurrences and patient-reported outcomes (PRO)). METHODS AND ANALYSIS: This is a multicentre prospective, case-matched control observational study to identify deficiencies in neuromuscular function following mTBI that may contribute to increased MSKI risk. Participants (aim to recruit 148, complete data collection on 124) will be classified into two cohorts; mTBI and control. All participants will undergo longitudinal (initial, 6 weeks post-initial, 12 weeks post-initial) comprehensive three-dimensional biomechanical (jump-landing; single leg hop; cut; gait), neuromuscular (interpolated twitch technique, muscular ramp contraction) and sensory (joint repositioning; light touch sensation) assessments to elucidate the underlying neuromuscular control mechanisms post-mTBI that may contribute to increased MSKI. Occurrences of MSKI and PROs (National Institutes of Health Patient-Reported Outcome Measurement Information System: Physical Function, Pain Interference, Depression, Anxiety; Brief Resilience Scale; Tampa Scale of Kinesiophobia), will be tracked monthly (up to 1 year) via electronic data capture platforms. ETHICS AND DISSEMINATION: The study received approval from the Walter Reed National Military Medical Center Institutional Review Board. Results will be made available to the associated funding agency and other researchers via conference proceedings and journal articles. TRIAL REGISTRATION NUMBER: NCT05122728.

Hooks Versus Pedicle Screws at the Upper Instrumented Level: An In Vitro Biomechanical Comparison.

STUDY DESIGN: Controlled laboratory study. OBJECTIVE: The aim was to compare motions at the upper instrumented vertebra (UIV) and supra-adjacent level (UIV+1) between two fixation techniques in thoracic posterior spinal fusion constructs. We hypothesized there would be greater motion at UIV+1 after cyclic loading across all constructs and bilateral pedicle screws (BPSs) with posterior ligamentous compromise would demonstrate the greatest UIV+1 range of motion. SUMMARY OF BACKGROUND DATA: Proximal junctional kyphosis is a well-recognized complication following long thoracolumbar posterior spinal fusion, however, its mechanism is poorly understood. MATERIALS AND METHODS: Twenty-seven thoracic functional spine units were randomly divided into three UIV fixation groups (n=9): (1) BPS, (2) bilateral transverse process hooks (TPHs), and (3) BPS with compromise of the posterior elements between UIV and UIV+1 (BPS-C). Specimens were tested on a servohydraulic materials testing system in native state, following instrumentation, and after cyclic loading. functional spine units were loaded in flexion-extension (FE), lateral bending, and axial rotation. RESULTS: After cyclic testing, the TPH group had a mean 29.4% increase in FE range of motion at UIV+1 versus 76.6% in the BPS group ( P <0.05). The BPS-C group showed an increased FE of 49.9% and 62.19% with sectioning of the facet joints and interspinous ligament respectively prior to cyclic testing. CONCLUSION: BPSs at the UIV led to greater motion at UIV+1 compared to bilateral TPH after cyclic loading. This is likely due to the increased rigidity of BPS compared to TPH leading to a "softer" transition between the TPH construct and native anatomy at the supra-adjacent level. Facet capsule compromise led to a 49.9% increase in UIV+1 motion, underscoring the importance of preserving the posterior ligamentous complex. Clinical studies that account for fusion rates are warranted to determine if constructs with a "soft transition" result in less proximal junctional kyphosis in vivo .

Survival of anterior cruciate ligament reconstructions in active-duty military populations.

PURPOSE: Anterior cruciate ligament tears and anterior cruciate ligament reconstruction (ACLR) are common in young athletes. The modifiable and non-modifiable factors contributing to ACLR failure and reoperation are incompletely understood. The purpose of this study was to determine ACLR failure rates in a physically high-demand population and identify the patient-specific risk factors, including prolonged time between diagnosis and surgical correction, that portend failure. METHODS: A consecutive series of military service members with ACLR with and without concomitant procedures (meniscus [M] and/or cartilage [C]) done at military facilities between 2008 and 2011 was completed via the Military Health System Data Repository. This was a consecutive series of patients without a history of knee surgery for two years prior to the primary ACLR. Kaplan-Meier survival curves were estimated and evaluated with Wilcoxon test. Cox proportional hazard models calculated hazard ratios (HR) with 95% confidence intervals (95% CI) to identify demographic and surgical factors that influenced ACLR failure. RESULTS: Of the 2735 primary ACLRs included in the study, 484/2,735 (18%) experienced ACLR failure within four years, including (261/2,735) (10%) undergoing revision ACLR and (224/2,735) (8%) due to medical separation. The factors that increased failure include Army Service (HR 2.19, 95% CI 1.67, 2.87), > 180 days from injury to ACLR (HR 1.550, 95% CI 1.157, 2.076), tobacco use (HR 1.429 95% CI 1.174, 1.738), and younger patient age (HR 1.024, 95% CI 1.004, 1.044). CONCLUSION: The overall clinical failure rate of service members with ACLR is 17.7% with minimum four-year follow-up, where more patients are likely to fail due to revision surgery than medical separation. The cumulative probability of survival at 4 years was 78.5%. Smoking cessation and treating ACLR patients promptly are modifiable risk factors impacting either graft failure or medical separation. LEVEL OF EVIDENCE: Level III.

Lower Extremity Musculoskeletal Injuries After Concussion in Collegiate Student-Athletes.

BACKGROUND: An association has been identified between concussion and lower extremity musculoskeletal injury (LEMSKI) after return to sports participation. However, the collegiate student-athlete studies have relied on relatively small single-institution studies, which limits generalizability. PURPOSE: To assess odds of, and time to, LEMSKI after concussion in US collegiate athletes, using the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP). STUDY DESIGN: Descriptive epidemiology study. METHODS: Data from the NCAA ISP during the 2010-2011 through 2019-2020 athletic seasons were considered for analysis. Frequency distributions were examined for details related to the initial and subsequent injuries (injuries to bone, bursa, joint, ligament, muscle, or tendon). Multivariable logistic regression models and random-effects Poisson regression models examined odds of time loss (TL) and non-time loss (NTL) LEMSKI after concussion, as well as the time interval between initial concussion and subsequent LEMSKI in a single athletic season, or initial musculoskeletal injury (MSKI) and subsequent LEMSKI in a single athletic season. Analyses were performed separately for football and other sports. RESULTS: A total of 31,556 initial injuries were recorded (football: 11,900; other sports: 19,656), which were followed by 0 or 1 injury in the same season. Overall, first injury type was not a significant predictor of subsequent LEMSKI, although certain contrasts yielded significant estimates. In football, the odds of NTL LEMSKI were higher after concussion than after upper extremity MSKI (UEMSKI; adjusted odds ratio [ORAdj], 1.56; 95% CI, 1.06-2.31). In football, the odds of TL LEMSKI were lower after concussion than after UEMSKI (ORAdj, 0.71; 95% CI, 0.51-0.99). No other significant effect estimates were observed for football or other sports. CONCLUSION: First injury type, either concussion or upper extremity, was not associated with an elevated risk of LEMSKI. Specifically, the results of this study did not identify an elevated odds of LEMSKI after a concussion. However, the authors observed greater odds of NTL LEMSKI and lower odds of TL LEMSKI in football.

Pre-neuromusculoskeletal injury Risk factor Evaluation and Post-neuromusculoskeletal injury Assessment for Return-to-duty/activity Enhancement (PREPARE) in military service members: a prospective, observational study protocol.

BACKGROUND: Non-battle related musculoskeletal injuries (MSKI) are one of the primary medical issues diminishing Service member medical readiness. The MSKI problem is challenging because it is difficult to assess all of the factors that increase MSKI risk and influence post-MSKI outcomes. Currently, there are no high-throughput, clinically-feasible, and comprehensive assessments to generate patient-centric data for informing pre- and post-MSKI risk assessment and mitigation strategies. The objective of the "Pre-neuromusculoskeletal injury Risk factor Evaluation and Post-neuromusculoskeletal injury Assessment for Return-to-duty/activity Enhancement (PREPARE)" study is to develop a comprehensive suite of clinical assessments to identify the patient-specific factors contributing to MSKI risks and undesired post-MSKI outcomes. METHODS: This is a phased approach, multi-center prospective, observational study (ClinicalTrials.gov number: NCT05111925) to identify physical and psychosocial factors contributing to greater MSKI risk and undesired post-MSKI outcomes, and to identify and validate a minimal set of assessments to personalize risk mitigation and rehabilitation strategies. In Phase I, one cohort (n = 560) will identify the physical and psychosocial factors contributing to greater MSKI risks (single assessment), while a second cohort (n = 780) will identify the post-MSKI physical and psychosocial factors contributing to undesired post-MSKI outcomes (serial assessments at enrollment, 4 weeks post-enrollment, 12 weeks post-enrollment). All participants will complete comprehensive movement assessments captured via a semi-automated markerless motion capture system and instrumented walkway, joint range of motion assessments, psychosocial measures, and self-reported physical fitness performance and MSKI history. We will follow participants for 6 months. We will identify the minimum set of clinical assessments that provide requisite data to personalize MSKI risk mitigation and rehabilitation strategies, and in Phase II validate our optimized assessments in new cohorts. DISCUSSION: The results of this investigation will provide clinically relevant data to efficiently inform MSKI risk mitigation and rehabilitation programs, thereby helping to advance medical care and retain Service members on active duty status. TRIAL REGISTRATION: PREPARE was prospectively registered on ClinicalTrials.gov (NCT05111925) on 5 NOV 2021, prior to study commencement.

The Military Orthopedics Tracking Injuries and Outcomes Network: A Solution for Improving Musculoskeletal Care in the Military Health System.

INTRODUCTION: Musculoskeletal injuries are an endemic amongst U.S. Military Service Members and significantly strain the Department of Defense's Military Health System. The Military Health System aims to provide Service Members, military retirees, and their families the right care at the right time. The Military Orthopedics Tracking Injuries and Outcomes Network (MOTION) captures the data that can optimize musculoskeletal care within the Military Health System. This report provides MOTION structural framework and highlights how it can be used to optimize musculoskeletal care. MATERIALS AND METHODS: MOTION established an internet-based data capture system, the MOTION Musculoskeletal Data Portal. All adult Military Health System patients who undergo orthopedic surgery are eligible for entry into the database. All data are collected as routine standard of care, with patients and orthopedic surgeons inputting validated global and condition-specific patient reported outcomes and operative case data, respectively. Patients have the option to consent to allow their standard of care data to be utilized within an institutional review board approved observational research study. MOTION data can be merged with other existing data systems (e.g., electronic medical record) to develop a comprehensive dataset of relevant information. In pursuit of enhancing musculoskeletal injury patient outcomes MOTION aims to: (1) identify factors which predict favorable outcomes; (2) develop models which inform the surgeon and military commanders if patients are behind, on, or ahead of schedule for their targeted return-to-duty/activity; and (3) develop predictive models to better inform patients and surgeons of the likelihood of a positive outcome for various treatment options to enhance patient counseling and expectation management. RESULTS: This is a protocol article describing the intent and methodology for MOTION; thus, to date, there are no results to report. CONCLUSIONS: MOTION was established to capture the data that are necessary to improve military medical readiness and optimize medical resource utilization through the systematic evaluation of short- and long-term musculoskeletal injury patient outcomes. The systematic enhancement of musculoskeletal injury care through data analyses aligns with the National Defense Authorization Act (2017) and Defense Health Agency's Quadruple Aim, which emphasizes optimizing healthcare delivery and Service Member medical readiness. This transformative approach to musculoskeletal care can be applied across disciplines within the Military Health System.

Repurposing existing products to accelerate injury recovery (REPAIR) of military relevant musculoskeletal conditions.

Musculoskeletal injuries (MSKIs) are a great hindrance to the readiness of the United States Armed Forces through lost duty time and reduced operational capabilities. While most musculoskeletal injuries result in return-to-duty/activity with no (functional) limitations, the healing process is often long. Long healing times coupled with the high frequency of musculoskeletal injuries make them a primary cause of lost/limited duty days. Thus, there exists an urgent, clinically unmet need for interventions to expedite tissue healing kinetics following musculoskeletal injuries to lessen their impact on military readiness and society as a whole. There exist several treatments with regulatory approval for other indications that have pro-regenerative/healing properties, but few have an approved indication for treating musculoskeletal injuries. With the immediate need for treatment options for musculoskeletal injuries, we propose a paradigm of Repurposing Existing Products to Accelerate Injury Recovery (REPAIR). Developing treatments via repurposing existing therapeutics for other indications has shown monumental advantages in both cost effectiveness and reduced time to bring to market compared to novel candidates. Thus, undertaking the needed research efforts to evaluate the effectiveness of promising REPAIR-themed candidates has the potential to enable near-term solutions for optimizing musculoskeletal injuries recovery, thereby addressing a top priority within the United States. Armed Forces. Herein, the REPAIR paradigm is presented, including example targets of opportunity as well as practical considerations for potential technical solutions for the translation of existing therapeutics into clinical practice for musculoskeletal injuries.

Biomechanical characterization of the foot-ground interaction among Service members with unilateral transtibial limb loss performing unconstrained drop-landings: Effects of drop height and added mass.

There exist limited data to guide the development of methodologies for evaluating impact resilience of prosthetic ankle-foot systems, particularly regarding human-device interaction in ecologically valid scenarios. The purpose of this study was to biomechanically characterize foot-ground interactions during drop-landings among Service members with and without unilateral transtibial limb loss. Seven males with, and seven males without, unilateral transtibial limb loss completed six drop-landing conditions consisting of all combinations of three heights (20 cm, 40 cm, 60 cm) and two loads (with and without a 22.2 kg weighted vest). Peak ground reaction forces (GRF), vertical GRF loading rate and impulse, as well as ankle-foot, knee, and hip joint negative (absorption) powers and work were compared across groups (i.e., contralateral side and prosthetic side vs. uninjured controls) by height and load conditions. Loading occurred primarily in the vertical direction, and increased with increasing drop height and/or with added load. Vertical GRFs were overall ~ 15% smaller on the prosthetic side (vs. controls) with similar loading rates across limbs/groups. From the most challenging condition (i.e., 60 cm with 22 kg load), ankle-foot absorption energies on the prosthetic side were 64.6 (7.2) J; corresponding values were 187.4 (8.9) J for the contralateral limb and 161.2 (6.7) J among uninjured controls. Better understanding biomechanical responses to drop-landings in ecological scenarios will help inform future iterations of mechanical testing methodologies for evaluating impact resilience of prosthetic ankle-foot systems (enhancing prescription criteria and return-to-activity considerations) as well as identifying and mitigating risk factors for long-term secondary complications within the contralateral limb (e.g., joint degeneration).

A Biomechanical Comparison of High-Tensile Strength Tape Versus High-Tensile Strength Suture for Tendon Fixation Under Cyclic Loading.

PURPOSE: To compare the biomechanical properties of high-tensile strength tape and high-tensile strength suture across 2 selected stitch techniques, the Krackow and whip stitch, in securing tendinous tissue during 5,000 cycles of nondestructive loading followed by a load to failure. METHODS: Fourteen matched pairs each of cadaveric Achilles, quadriceps, and patellar tendons (n = 84) were randomly assigned to either Krackow or whip stitch and sutured with either 2-mm high-tensile strength tape or No. 2 high-tensile strength suture. Specimens were preloaded to 20 N, cyclically loaded from 20 to 200 N for 5,000 cycles at 2 Hz, and then loaded to failure at 200 mm/min. Linear mixed models evaluated the effects of suture material and stitch technique on cyclic normalized tendon-suture elongation, total normalized tendon-suture elongation at 5,000 cycles, and maximum load at failure. RESULTS: Across all suture constructs, normalized elongation was greater during the initial 10 cycles, compared with all subsequent cycling intervals (all P < .001). There was less total normalized elongation (ß = -0.239; P = .007) and greater maximum load at failure in tape (ß = 163.71; P = .014) when used in the Krackow stitch compared with the whip stitch. CONCLUSIONS: Our findings indicate that tape used in the Krackow stitch maintains the most favorable fixation strength after enduring cyclic loading, with greater maximum load at failure. In addition, overall normalized elongation during long-term cyclic loading was predominately affected by the stitch technique used, regardless of the suture material; however, tape allowed less normalized elongation during the initial loading cycles, especially when placed in the whip stitch. CLINICAL RELEVANCE: Understanding the potential short- and long-term outcomes of suture material and stitch technique on securing tendinous tissue under repetitive stresses can help inform clinicians on optimal tendon fixation techniques for early postoperative activities.

Generating the American Shoulder and Elbow Surgeons Score Using Multivariable Predictive Models and Computer Adaptive Testing to Reduce Survey Burden.

BACKGROUND: The preferred patient-reported outcome measure for the assessment of shoulder conditions continues to evolve. Previous studies correlating the Patient-Reported Outcomes Measurement Information System (PROMIS) computer adaptive tests (CATs) to the American Shoulder and Elbow Surgeons (ASES) score have focused on a singular domain (pain or physical function) but have not evaluated the combined domains of pain and physical function that compose the ASES score. Additionally, previous studies have not provided a multivariable prediction tool to convert PROMIS scores to more familiar legacy scores. PURPOSE: To establish a valid predictive model of ASES scores using a nonlinear combination of PROMIS domains for physical function and pain. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3. METHODS: The Military Orthopaedics Tracking Injuries and Outcomes Network (MOTION) database is a prospectively collected repository of patient-reported outcomes and intraoperative variables. Patients in MOTION research who underwent shoulder surgery and completed the ASES, PROMIS Physical Function, and PROMIS Pain Interference at varying time points were included in the present analysis. Nonlinear multivariable predictive models were created to establish an ASES index score and then validated using "leave 1 out" techniques and minimal clinically important difference /substantial clinical benefit (MCID/SCB) analysis. RESULTS: A total of 909 patients completed the ASES, PROMIS Physical Function, and PROMIS Pain Interference at presurgery, 6 weeks, 6 months, and 1 year after surgery, providing 1502 complete observations. The PROMIS CAT predictive model was strongly validated to predict the ASES (Pearson coefficient = 0.76-0.78; R2 = 0.57-0.62; root mean square error = 13.3-14.1). The MCID/SCB for the ASES was 21.7, and the best ASES index MCID/SCB was 19.4, suggesting that the derived ASES index is effective and can reliably re-create ASES scores. CONCLUSION: The PROMIS CAT predictive models are able to approximate the ASES score within 13 to 14 points, which is 7 points more accurate than the ASES MCID/SCB derived from the sample. Our ASES index algorithm, which is freely available online (https://osf.io/ctmnd/), has a lower MCID/SCB than the ASES itself. This algorithm can be used to decrease patient survey burden by 11 questions and provide a reliable ASES analog to clinicians.

Validation of a Commercially Available Markerless Motion-Capture System for Trunk and Lower Extremity Kinematics During a Jump-Landing Assessment.

CONTEXT: Field-based, portable motion-capture systems can be used to help identify individuals at greater risk of lower extremity injury. Microsoft Kinect-based markerless motion-capture systems meet these requirements; however, until recently, these systems were generally not automated, required substantial data postprocessing, and were not commercially available. OBJECTIVE: To validate the kinematic measures of a commercially available markerless motion-capture system. DESIGN: Descriptive laboratory study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 20 healthy, physically active university students (10 males, 10 females; age = 20.50 ± 2.78 years, height = 170.36 ± 9.82 cm, mass = 68.38 ± 10.07 kg, body mass index = 23.50 ± 2.40 kg/m2). INTERVENTION(S): Participants completed 5 jump-landing trials. Kinematic data were simultaneously recorded using Kinect-based markerless and stereophotogrammetric motion-capture systems. MAIN OUTCOME MEASURE(S): Sagittal- and frontal-plane trunk, hip-joint, and knee-joint angles were identified at initial ground contact of the jump landing (IC), for the maximum joint angle during the landing phase of the initial landing (MAX), and for the joint-angle displacement from IC to MAX (DSP). Outliers were removed, and data were averaged across trials. We used intraclass correlation coefficients (ICCs [2,1]) to assess intersystem reliability and the paired-samples t test to examine mean differences (α ≤ .05). RESULTS: Agreement existed between the systems (ICC range = -1.52 to 0.96; ICC average = 0.58), with 75.00% (n = 24/32) of the measures being validated (P ≤ .05). Agreement was better for sagittal- (ICC average = 0.84) than frontal- (ICC average = 0.35) plane measures. Agreement was best for MAX (ICC average = 0.77) compared with IC (ICC average = 0.56) and DSP (ICC average = 0.41) measures. Pairwise comparisons identified differences for 18.75% (6/32) of the measures. Fewer differences were observed for sagittal- (0.00%; 0/15) than for frontal- (35.29%; 6/17) plane measures. Between-systems differences were equivalent for MAX (18.18%; 2/11), DSP (18.18%; 2/11), and IC (20.00%; 2/10) measures. The markerless system underestimated sagittal-plane measures (86.67%; 13/15) and overestimated frontal-plane measures (76.47%; 13/17). No trends were observed for overestimating or underestimating IC, MAX, or DSP measures. CONCLUSIONS: Moderate agreement existed between markerless and stereophotogrammetric motion-capture systems. Better agreement existed for larger (eg, sagittal-plane, MAX) than for smaller (eg, frontal-plane, IC) joint angles. The DSP angles had the worst agreement. Markerless motion-capture systems may help clinicians identify individuals at greater risk of lower extremity injury.

A Longitudinal Comparison of Patient-Reported Outcomes Measurement Information System to Legacy Scales in Knee and Shoulder Arthroscopy Patients.

PURPOSE: The purpose of this prospective correlational study was to compare the psychometric properties of the Defense and Veterans Pain Rating Scale (DVPRS) and Patient-Reported Outcomes Measurement Information System (PROMIS) scales with those of traditional legacy scales over a longitudinal postoperative period in patients undergoing arthroscopic procedures. METHODS: Active-duty military personnel undergoing shoulder and knee arthroscopic procedures completed the DVPRS, PROMIS, and legacy scales preoperatively and again at 3 months postoperatively. Rolling correlation coefficients (rrm) were used to assess the concurrent validity between the DVPRS average pain scores and computer adaptive testing PROMIS scales (Anxiety, Depression, Pain Behavior, Pain Interference, Mobility, Sleep Disturbance, Satisfaction With Social Roles, and Upper Extremity Physical Function) and the legacy scales (American Shoulder and Elbow Surgeons [ASES] scale, Shoulder Activity Scale, International Knee Documentation Committee [IKDC] questionnaire, Single Assessment Numeric Evaluation [SANE], Marx Activity Rating Scale, and Veterans RAND 12-Item Health Survey). RESULTS: A total of 121 participants completed the scales preoperatively, 80 completed them at 3 months postoperatively, and 59 (49% of participants) completed them at both times. Rolling correlation coefficients between PROMIS Pain Interference (rrm = -0.41, P = .006), Satisfaction With Social Roles (rrm = 0.56, P < .001), and Upper Extremity (rrm = 0.71, P < .001) scores showed acceptable concurrent validity with ASES scores over a longitudinal postoperative period. DVPRS scores (rrm = -0.69, P = .002) and PROMIS Pain Behavior (rrm = -0.57, P = .018), Pain Interference (rrm = -0.71, P = .001), Sleep Disturbance (rrm = -0.64, P = .005), and Mobility (rrm = 0.65, P = .005) scores showed acceptable concurrent validity with IKDC scores. There was poor correlation between the PROMIS and DVPRS scores and the Single Assessment Numeric Evaluation, Marx Activity Rating Scale, Shoulder Activity Scale, and Veterans RAND 12-Item Health Survey scores. CONCLUSIONS: PROMIS scales measuring physical function, pain presentation, and other health domains showed acceptable concurrent validity with ASES and IKDC scores. By integrating the prospective collection of biopsychosocial PROMIS scales into practice, it is possible for clinicians in orthopaedic settings to assess changes in validated patient-reported outcomes to inform patient-centered care planning throughout the postoperative recovery period. LEVEL OF EVIDENCE: Level II, prospective comparative study (with not all participants completing follow-up).

Trunk and Lower Extremity Movement Patterns, Stress Fracture Risk Factors, and Biomarkers of Bone Turnover in Military Trainees.

CONTEXT: Military service members commonly sustain lower extremity stress fractures (SFx). How SFx risk factors influence bone metabolism is unknown. Understanding how SFx risk factors influence bone metabolism may help to optimize risk-mitigation strategies. OBJECTIVE: To determine how SFx risk factors influence bone metabolism. DESIGN: Cross-sectional study. SETTING: Military service academy. PATIENTS OR OTHER PARTICIPANTS: Forty-five men (agepre = 18.56 ± 1.39 years, heightpre = 176.95 ± 7.29 cm, masspre = 77.20 ± 9.40 kg; body mass indexpre = 24.68 ± 2.87) who completed Cadet Basic Training (CBT). Individuals with neurologic or metabolic disorders were excluded. INTERVENTION(S): We assessed SFx risk factors (independent variables) with (1) the Landing Error Scoring System (LESS), (2) self-reported injury and physical activity questionnaires, and (3) physical fitness tests. We assessed bone biomarkers (dependent variables; procollagen type I amino-terminal propeptide [PINP] and cross-linked collagen telopeptide [CTx-1]) via serum. MAIN OUTCOME MEASURE(S): A markerless motion-capture system was used to analyze trunk and lower extremity biomechanics via the LESS. Serum samples were collected post-CBT; enzyme-linked immunosorbent assays determined PINP and CTx-1 concentrations, and PINP : CTx-1 ratios were calculated. Linear regression models demonstrated associations between SFx risk factors and PINP and CTx-1 concentrations and PINP : CTx-1 ratio. Biomarker concentration mean differences with 95% confidence intervals were calculated. Significance was set a priori using α ≤ .10 for simple and α ≤ .05 for multiple regression analyses. RESULTS: The multiple regression models incorporating LESS and SFx risk factor data predicted the PINP concentration (R2 = 0.47, P = .02) and PINP : CTx-1 ratio (R2 = 0.66, P = .01). The PINP concentration was increased by foot internal rotation, trunk flexion, CBT injury, sit-up score, and pre- to post-CBT mass changes. The CTx-1 concentration was increased by heel-to-toe landing and post-CBT mass. The PINP : CTx-1 ratio was increased by foot internal rotation, lower extremity sagittal-plane displacement (inversely), CBT injury, sit-up score, and pre- to post-CBT mass changes. CONCLUSIONS: Stress fracture risk factors accounted for 66% of the PINP : CTx-1 ratio variability, a potential surrogate for bone health. Our findings provide insight into how SFx risk factors influence bone health. This information can help guide SFx risk-mitigation strategies.

Single-Legged Hop and Single-Legged Squat Balance Performance in Recreational Athletes With a History of Concussion.

CONTEXT: Researchers have suggested that balance deficiencies may linger during functional activities after concussion recovery. OBJECTIVE: To determine whether participants with a history of concussion demonstrated dynamic balance deficits as compared with control participants during single-legged hops and single-legged squats. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 15 previously concussed participants (6 men, 9 women; age = 19.7 ± 0.9 years, height = 169.2 ± 9.4 cm, mass = 66.0 ± 12.8 kg, median time since concussion = 126 days [range = 28-432 days]) were matched with 15 control participants (6 men, 9 women; age = 19.7 ± 1.6 years, height = 172.3 ± 10.8 cm, mass = 71.0 ± 10.4 kg). INTERVENTION(S): During single-legged hops, participants jumped off a 30-cm box placed at 50% of their height behind a force plate, landed on a single limb, and attempted to achieve a stable position as quickly as possible. Participants performed single-legged squats while standing on a force plate. MAIN OUTCOME MEASURE(S): Time to stabilization (TTS; time for the normalized ground reaction force to stabilize after landing) was calculated during the single-legged hop, and center-of-pressure path and speed were calculated during single-legged squats. Groups were compared using analysis of covariance, controlling for average days since concussion. RESULTS: The concussion group demonstrated a longer TTS than the control group during the single-legged hop on the nondominant leg (mean difference = 0.35 seconds [95% confidence interval = 0.04, 0.64]; F2,27 = 5.69, P = .02). No TTS differences were observed for the dominant leg (F2,27 = 0.64, P = .43). No group differences were present for the single-legged squat on either leg (P ≥ .11). CONCLUSIONS: Dynamic balance-control deficits after concussion may contribute to an increased musculoskeletal injury risk. Given our findings, we suggest that neuromuscular deficits currently not assessed after concussion may linger. Time to stabilization is a clinically applicable measure that has been used to distinguish patients with various pathologic conditions, such as chronic ankle instability and anterior cruciate ligament reconstruction, from healthy control participants. Whereas the single-legged squat may not sufficiently challenge balance control, future study of the more dynamic single-legged hop is needed to determine its potential diagnostic and prognostic value after concussion.

Combat and Noncombat Musculoskeletal Injuries in the US Military.

Musculoskeletal Injuries (MSKI) are exceedingly common in the US Military, resulting in compromised military medical readiness and a substantial burden on both health care and financial resources. Severe combat-related MSKI sustained during nearly 2 decades of conflict in Iraq and Afghanistan have resulted in frequently devastating injuries that challenge acute care capabilities, require extensive rehabilitation, and often result in long-term disability. Non-combat-related MSKI, while often less severe, are far more common than combat-related MSKI and overall cause a substantially greater number of lost duty days and nondeployable Service Members. Given the strain placed on health care and financial resources by MSKI, further efforts must be directed towards prevention, treatment, and rehabilitative strategies in order to mitigate the burden of MSKI in the US Military.

Effect of Single-Leg Squat Speed and Depth on Dynamic Postural Control Under Single-Task and Dual-Task Paradigms.

Although single-leg squats are a common dynamic balance clinical assessment, little is known about the relationship between parameters that influence squat movement and postural control performance. The objective of this study was to determine the relationships between squat parameters (speed and depth) and postural control under single task and dual task. A total of 30 healthy college students performed single-leg squats under single task and dual task with Stroop. Random-intercepts generalized linear mixed models determined the effect of squat parameters on center of pressure (CoP) parameters. For each 1-cm·s-1 increase in squat speed, sway range (mediolateral: ß = -0.03; anteroposterior: ß = -0.05) and area (ß = -0.25) decreased, whereas sway speed (mediolateral: ß = 0.05; anteroposterior: ß = 0.29; total: ß = 0.29) increased. For each 1-cm increase in squat depth, sway range (mediolateral: ß = 0.05; anteroposterior: ß = 0.20) and area (ß = 0.72) increased, whereas sway speed (anteroposterior: ß = -0.14; total: ß = -0.14) decreased. Compared with single task, the association between total and anteroposterior sway speed and squat speed was stronger under dual task. Clinicians and researchers should consider monitoring squat speed and depth when assessing dynamic balance during single-leg squats, as these parameters influence postural control, especially under dual task.

A History of Shoulder Instability in the Military: Where We Have Been and What We Have Learned.

Introduction: Shoulder instability is one of the most common pathologies seen by the orthopedic sports medicine surgeon. With a uniquely young, high-demand patient population in the U.S. Military, the incidence of shoulder instability is remarkably more common than the civilian population. As such, military orthopedic surgeons and sports medicine and shoulder specialists have developed a unique understanding and experience of shoulder instability. The historical advances of shoulder instability in the military have been instrumental in understanding the epidemiology, evaluation, pathology, treatment of first-time shoulder subluxations and dislocations, operative and non-operative treatment options, arthroscopic and open stabilization methods, management of the in-season athlete, treatment of combined and circumferential labral pathology, and associated pathology. Methods: The purpose of this article is to chronicle the experience of military orthopedic surgeons in treating shoulder instability. We discuss how this unique experience has led to a better understanding of the epidemiology and pathology of this condition and how we have adapted our clinical practice to improve patient outcomes. Results: The historical contribution of U.S. Military orthopedics to the understanding of shoulder instability has been monumental. This article reviews the evolution of shoulder instability treatment and the understanding as it has evolved in the U.S. Military. It further elaborates on our understanding of the epidemiology of shoulder instability in the U.S. Military, with attention given to our incidence of 1.69 per 1000 person-years, approximately 20 times higher incidence than the general population. We discuss known risk factors for dislocation that contribute to this incidence, which are specific to military service. We address pathologic changes seen following a first-time instability event, including an analysis of labral injury and the role of these pathologic changes in recurrent instability. We also review our results from arthroscopic evaluation of first-time dislocations and compare the pathologic changes with those following a first-time subluxation. Evaluation of treatment outcomes is discussed, comparing operative and non-operative results as well as open and arthroscopic stabilization in the U.S. Military population and contact/collision athletes. Finally, we address how these results drive our current treatment algorithm. Discussion and Conclusion: The physical demands of military service result in a high rate of shoulder instability relative to the general population. For years military orthopedic surgeons have sought to better understand this pathology and learn how to optimally manage it so as to reduce this heavy burden of disease. This article discusses our experience with treating shoulder instability, provides an overview of the lessons learned, and provides a historical perspective for the evolution of shoulder instability understanding in the U.S. Military.

The Influence of Verbal and Tactile Feedback on Electromyographic Amplitude of the Shoulder Musculature During Common Therapeutic Exercises.

CONTEXT: Verbal and tactile feedback (VTF) during rehabilitation exercises can increase muscle activation, thus improving the therapeutic benefits. However, it is unclear which feedback method elicits the greatest electromyographic (EMG) amplitude. OBJECTIVE: To determine if the addition of tactile to verbal feedback (VF) increases EMG amplitude of selected shoulder musculature during scapular plane elevation (Ys), shoulder horizontal abduction with external rotation (Ts), and scapular retraction with external rotation (Ws). DESIGN: Repeated-measures cross-over design. SETTING: Biomechanics laboratory. PARTICIPANTS: A total of 30 physically active adults volunteered for this study-age = 20.23 (1.25) years; height = 1.71 (0.073) m; and mass = 70.11 (15.14) kg. INTERVENTIONS: Electromyography of the serratus anterior; upper, middle, and lower trapezii; and anterior and posterior deltoids was recorded during Ys, Ts, and Ws with VTF and VF alone during separate testing sessions. Participants completed baseline trials without feedback, then received VTF and VF across 2 counterbalanced sessions. MAIN OUTCOME MEASURES: Difference scores were calculated between prefeedback and postfeedback interventions, and the difference score between baseline measurements was used as a control. One-way analysis of variance of the difference scores was used to evaluate the influence of VTF and VF on EMG amplitude during Ys, Ts, and Ws. RESULTS: There was a significant difference between conditions for EMG amplitude of the middle trapezius (F2,28 = 4.09, P = .02) and serratus anterior (F2,28 = 3.91, P = .03) during Ys, the middle trapezius (F2,28 = 7.82, P = .001) during Ws, and the upper (F2,28 = 3.61, P = .03) and middle trapezii (F2,28 = 5.81, P = .01) during Ts. Post hoc testing revealed that both feedback conditions elicited greater EMG amplitude compared with no feedback, but there were no significant differences between the feedback conditions. CONCLUSIONS: The addition of tactile feedback to VF does not increase EMG amplitude compared with VF alone. This study indicates that feedback, regardless of type, is more beneficial than providing no feedback, for increasing EMG amplitude.